The present invention provides 1,4-diaryl-2,3-difluoro-2-butene compounds which are useful as insecticidal and acaricidal agents. The compounds are also useful for protecting plants from damage caused by insect and acarid attack and infestation.
1,4-diaryl-2,3-difluoro-2-butenes of the present invention have the structural formula I 
wherein
Ar is
phenyl which is unsubstituted or substituted with any combination of from one to three halogen, C1-C4alkyl, C1-C4-haloalkyl, C1-C4-alkoxy, C1-C4-haloalkoxy or hydroxy groups,
1- or 2-naphthyl which is unsubstituted or substituted with any combination of from one to three halogen, C1-C4-alkyl, C1-C4-haloalkyl, C1-C4-alkoxy or C1-C4-haloalkoxy groups, or
a 5- or 6-membered heteroaromatic ring containing one to four nitrogen atoms or one to three nitrogen atoms and one sulfur atom or oxygen atom or one or two sulfur and/or oxygen atoms which is unsubstituted or substituted with any combination of from one to three halogen, C1-C4-alkyl, C1-C4haloalkyl, C1-C4-alkoxy or C1-C4-haloalkoxy groups;
R is C2-C6-alkenyl, C4-C6-cycloalkenyl or C1-C2-alkoxy-C2-C6-alkyl;
Ar1 is
phenoxyphenyl which is unsubstituted or substituted with any combination of from one to six halogen, C1-C4-alkyl, C1-C4-haloalkyl, C1-C4-alkoxy or C1-C4-haloalkoxy groups,
phenyl which is unsubstituted or substituted with any combination of from one to five halogen, C1-C4-alkyl, C1-C4-haloalkyl, C1-C4-alkoxy or C1-C4-haloalkoxy groups,
biphenyl which is unsubstituted or substituted with any combination of from one to five halogen, C1-C4-alkyl, C1-C4-haloalkyl, C1-C4-alkoxy or C1-C4-haloalkoxy groups,
phenoxypyridyl which is unsubstituted or substituted with any combination of from one to five halogen, C1-C4-alkyl, C1-C4-haloalkyl C1-C4-alkoxy or C1-C4-haloalkoxy groups,
benzylpyridyl which is unsubstituted or substituted with any combination of from one to five halogen, C1-C4-alkyl, C1-C4-haloalkyl, C1-C4-alkoxy or C1-C4-haloalkoxy groups,
benzylphenyl which is unsubstituted or substituted with any combination of from one to five halogen, C1-C4-alkyl, is C1-C4-haloalkyl, C1-C4-alkoxy or C1-C4-haloalkoxy groups,
benzoylphenyl which is unsubstituted or substituted with any combination of from one to five halogen, C1-C4-alkyl, C1-C4-haloalkyl, C1-C4-alkoxy or C1-C4-haloalkoxy groups,
1- or 2-naphthyl which is unsubstituted or substituted with any combination of from one to three halogen, C1-C4-alkyl, C1-C4-haloalkyl, C1-C4-alkoxy or C1-C4-haloalkoxy groups, or
a 5- or 6-membered heteroaromatic ring containing one to four nitrogen atoms or one to three nitrogen atoms and one sulfur atom or oxygen atom or one or two sulfur and/or oxygen atoms which is unsubstituted or substituted with any combination of from one to three halogen, C1-C4-alkyl, C1-C4-haloalkyl, C1-C4-alkoxy or C1-C4-haloalkoxy groups, and
the optical isomers thereof, and
the (E)- and (Z)-isomers thereof.
This invention also provides intermediates and methods for the preparation of compounds of formula I, compositions containing the compounds, and methods for using the compounds and compositions.
U.S. Pat. No. 5,248,834 generically discloses certain 1-aryl-1-(3-aryl-1,2-difluoroprop-1-enyl)cyclopropane compounds.
EP-A 916 640 describes certain insecticidal and acaricidal 1,4-diaryl-2,3-difluoro-2-butenes, as well as methods for their preparation. Said application, however, does not disclose 1,4-diaryl-2,3-difluoro-2-butenes having alkoxy alkyl or alkenyl substituents in the 1-position.
The insecticidal and acaricidal activity of the compounds disclosed in the above-mentioned prior art in many cases is not fully satisfying.
It was, therefore, an object of the present invention to provide compounds which are more effective for the control of insect and acarid pests.
Accordingly, the 1,4-diaryl-2,3-difluoro-2-butene compounds of formula I have been found. Furthermore, intermediates and methods for the preparation of compounds of formula I as well as compositions containing them have been found.
The present invention also provides a method for the control of insect or acarid pests which comprises contacting said pests or their food supply, habitat or breeding grounds with a pesticidally effective amount of a compound of formula I.
The present invention also provides a method for the protection of growing plants from attack or infestation by insect or acarid pests which comprises applying to the foliage of the plants, or to the soil or water in which they are growing, a pesticidally effective amount of a compound of formula I.
In formula I above, 5- and 6-membered heteroaromatic rings containing one to four nitrogen atoms or one to three nitrogen atoms and one sulfur atom or oxygen atom or one or two sulfur and/or oxygen atoms include, but are not limited to, pyridyl, pyrazolyl, imidazolyl, triazolyl, isoxazolyl, tetrazolyl, pyrazinyl, pyridazinyl, triazinyl, furanyl, thienyl and thiazolyl rings each unsubstituted or substituted as described in formula I above.
Exemplary of halogen hereinabove are fluorine, chlorine, bromine and iodine;
The term xe2x80x9calkylxe2x80x9d is defined as a saturated, straight or branched chain hydrocarbon with 1 to 4 or 2 to 6 carbon atoms, such as methyl, ethyl, propyl, 1-methyl-ethyl, butyl, 1-methyl-propyl, 2-methyl-propyl, 1,1-dimethyl-propyl, pentyl, 1-methyl-butyl, 2-methyl-butyl, 3-methyl-butyl, 2,2-dimethyl-propyl, 1-ethyl-propyl, hexyl, 1,1-dimethyl-propyl, 1,2-dimethyl-propyl, 1-methyl-pentyl, 2-methyl-pentyl, 3-methyl-pentyl, 4-methyl-pentyl, 1,1-dimethyl-butyl, 1,2-dimethyl-butyl, 1,3-dimethyl-butyl, 2,2-dimethyl-butyl, 2,3-dimethyl-butyl, 3,3-dimethyl-butyl, 1-ethyl-butyl, 2-ethyl-butyl, 1,1,2-trimethyl-propyl, 1,2,2-tri-methyl-propyl, 1-ethyl-1-methyl-propyl und 1-ethyl-2-methyl-propyl;
The term xe2x80x9calkoxyxe2x80x9d is defined as a saturated, straight or branched chain hydrocarbon with 1 to 2 or 4 carbon atoms (as described above) which is bond to the backbone via an oxygen (xe2x80x94Oxe2x80x94) atom;
The term xe2x80x9ccycloalkylxe2x80x9d is defined as a monocyclic, saturated hydrocarbon group with 3 to 6 carbon ring atoms, such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl;
The term xe2x80x9chaloalkylxe2x80x9d is defined as an alkyl group, as defined above, wherein the hydrogen atoms may be partially or totally substituted with halogen atoms as defined above, wherein the halogen atoms may be the same or different, for example C1-C2-haloalkyl such as chloro-methyl, bromomethyl, dichloro-methyl, trichloro-methyl, fluoro-methyl, difluoro-methyl, trifluoro-methyl, chloro-fluoro-methyl, dichlorofluoro-methyl, chloro-difluoro-methyl, 1-chloro-ethyl, 1-bromo-ethyl, 1-fluoro-ethyl, 2-fluoro-ethyl, 2,2-difluoro-ethyl, 2,2,2-trifluoro-ethyl, 2-chloro-2-fluoro-ethyl, 2-chloro-2,2-difluoro-ethyl, 2,2-dichloro-2-fluoro-ethyl, 2,2,2-trichloro-ethyl and pentafluoro-ethyl;
The term xe2x80x9chaloalkoxyxe2x80x9d is defined as an alkoxy group as defined above, wherein the hydrogen atoms may be partially or totally substituted with one or more halogen atoms as defined above, wherein the halogen atoms may be the same or different;
The term halocycloalkyl is defined as a cycloalkyl group as defined above, wherein the hydrogen atoms may be partially or totally substituted with one or more halogen atoms as defined above, wherein the halogen atoms may be the same or different;
The term xe2x80x9calkenylxe2x80x9d is defined as an unsaturated, straight or branched chain hydrocarbon with 2 to 6 carbon atoms and a double bond in an arbitrary position, such as ethenyl, 1-propenyl, 2-propenyl, 1-methyl-ethenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1-methyl-1-propenyl, 2-methyl-1-propenyl, 1-methyl-2-propenyl, 2-methyl-2-propenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, 1-methyl-1-butenyl, 2-methyl-1-butenyl, 3-methyl-1-butenyl, 1-methyl-2-butenyl, 2-methyl-2-butenyl, 3-methyl-2-butenyl, 1-methyl-3-butenyl, 2-methyl-3-butenyl, 3-methyl-3-butenyl, 1,1-dimethyl-2-propenyl, 1,2-dimethyl-1-propenyl, 1,2-dimethyl-2-propenyl, 1-ethyl-1propenyl, 1-ethyl-2-propenyl, 1-hexenyl, 2-hexenyl, 3-hexenyl, 4-hexenyl, 5-hexenyl, 1-methyl-1-pentenyl, 2-methyl-1-pentenyl, 3-methyl-1-pentenyl, 4-methyl-1-pentenyl, 1-methyl-2-pentenyl, 2-methyl-2-pentenyl, 3-methyl-2-pentenyl, 4-methyl-2-pentenyl, 1-methyl-3-pentenyl, 2-methyl-3pentenyl, 3-methyl-3-pentenyl, 4-methyl-3-pentenyl, 1-methyl-4-pentenyl, 2-methyl-4-pentenyl 3-methyl-4-pentenyl, 4-methyl-4-pentenyl, 1,1-dimethyl-2-butenyl, 1,1-dimethyl-3-butenyl, 1,2-dimethyl-1-butenyl, 1,2-dimethyl-2-butenyl, 1,2-dimethyl-3-butenyl, 1,3-dimethyl-1-butenyl, 1,3-dimethyl-2-butenyl, 1,3-dimethyl-3-butenyl, 2,2-dimethyl-3-butenyl, 2,3-dimethyl-1-butenyl, 2,3-dimethyl-2-butenyl, 2,3-dimethyl-3-butenyl, 3,3-dimethyl-1-butenyl, 3,3-dimethyl-2-butenyl, 1-ethyl-1-butenyl, 1-ethyl-2-butenyl, 1-ethyl-3-butenyl, 2-ethyl-1-butenyl, 2-ethyl-2-butenyl, 2-ethyl-3-butenyl, 1,1,2-trimethyl-2-propenyl, 1-ethyl-1-methyl-2-propenyl, 1-ethyl-2-methyl-1propenyl and 1-ethyl-2-methyl-2-propenyl.
The term xe2x80x9ccycloalkenylxe2x80x9d is defined as an unsaturated, monocyclic hydrocarbon group with 4 to 6 carbon atoms with one double bond in an arbitrary position, such as cyclobutene, cyclopentene, and cyclohexene.
Wavy lines in structural formulae depict the carbon-carbon double bond in both the E- or the Z-isomeric configuration.
Preferred pesticidal agents of formula I are those wherein the variables have the following meanings, each alone or in combination:
Preferred are compounds of formula I wherein Ar is phenyl which is unsubstituted or substituted with any combination of from one to three halogen, C1-C4-alkyl, C1-C4-haloalkyl, C1-C4-alkoxy or C1-C4-haloalkoxy groups.
More preferred are compounds of formula I wherein Ar is phenyl which is unsubstituted or substituted with any combination of from one to three halogen, preferably chlorine.
Most preferred are compounds of formula I wherein Ar is 4-chlorophenyl.
Also preferred are compounds of formula I wherein R is C2-C4-alkenyl or C1-C2-alkoxy-C2-C6-alkyl.
Especially preferred are compounds of formula I wherein R is C2-C4-alkenyl, preferably C2-C3-alkenyl.
Furthermore, especially preferred are compounds of formula I wherein R is C1-C2-alkoxy-C2-C4-alkyl, preferably C1-C2-alkoxy-C2-C3-alkyl.
Most preferred are compounds of formula I wherein R is 2-methoxyethyl, vinyl or allyl.
Moreover, compounds of formula I are preferred wherein Ar1 is
3-phenoxyphenyl which is unsubstituted or substituted with any combination of from one to six halogen, C1-C4-alkyl, C1-C4-haloalkyl, C1-C4-alkoxy or C1-C4-haloalkoxy groups,
3-biphenyl which is unsubstituted or substituted with any combination of from one to five halogen, C1-C4-alkyl, C1-C4-haloalkyl, C1-C4-alkoxy or C1-C4-haloalkoxy groups, or
3-benzylphenyl which is unsubstituted or substituted with any combination of from one to five halogen, C1-C4-alkyl, C1-C4-haloalkyl, C1-C4-alkoxy or C1-C4-haloalkoxy groups.
More preferred are compounds of formula I wherein Ar1 is 3-phenoxy-phenyl which is unsubstituted or substituted with any combination of from one to six halogen, C1-C4-alkyl, C1-C4-haloalkyl, C1-C4-alkoxy or C1-C4-haloalkoxy groups.
Especially preferred are compounds of formula I wherein Ar1 is 3-phenoxyphenyl which is unsubstituted or substituted with any combination of from one to six halogen, preferably fluorine.
Most preferred insecticidal and acaricidal compounds of formula I agents are those wherein Ar is phenyl which is unsubstituted or substituted with any combination of from one to three halogen, C1-C4-alkyl, C1-C4-haloalkyl, C1-C4-alkoxy or C1-C4-haloalkoxy groups;
R is C2-C3-alkenyl or C1-C2-alkoxy-C2-C3-alkyl; and
Ar1 is 3-phenoxyphenyl which is unsubstituted or substituted with any combination of from one to six halogen, C1-C4-alkyl, C1-C4-haloalkyl, C1-C4-alkoxy or C1-C4-haloalkoxy groups.
In a preferred embodiment of the present invention, the fluorine atoms attached to the carbon atoms of the double bond in the formula I compounds are in the (E)-configuration with respect to each other.
Formula I compounds of this invention which are particularly effective insecticidal agents include
1-[(2E)-4-(4-chlorophenyl)-2,3-difluoro-6-methoxy-2-hexenyl]-3-phenoxybenzene;
1[(2E)-4-(4-chlorophenyl)-2,3-difluoro-2,6-heptadienyl]-3-phenoxybenzene;
1-[(2E)-4-(4-chlorophenyl)-2,3-difluoro-2,5-hexadienyl]-3-phenoxybenzene; and
4-[(2E)-4-(4-chlorophenyl)-2,3-difluoro-6-methoxy-2-hexenyl]-1-fluoro-2-phenoxybenzene.
Compounds of formula I may be prepared as described in EP-A 916 640 and illustrated in Flow Diagram I, by reacting 1,1,2-trifluoro-1-propenes of formula II.1 with a defluorinating agent such as sodium bis(2-methoxyethoxy)aluminum hydride and a mineral acid such as hydrochloric acid to form 1,2-difluoro-1-propene compounds of formula II.2, and sequentially reacting such formula II.2 compounds with a base such as an alkyllithium base, preferably n-butyllithium, zinc chloride, tetra-kis(triphenylphosphine)palladium(0) and a substituted methyl halide of formula IV, wherein Z is halogen, preferably chlorine, bromine or iodine and Ar1 is as defined for compounds of formula I above to afford compounds of formula I. 
Compounds of formula II.1 may be prepared as described in J. Amer. Chem. Soc. (1986), 108, p. 4229 to 4230.
Alternatively, compounds of formula I wherein R is vinyl (Ia) or allyl (Ic) may be prepared from compounds of formula Ib, wherein R is 2-methoxyethyl, as depicted in Flow Diagrams II and III, respectively.
2-Methoxyethyl compounds of formula Ib, prepared by the method depicted in Flow Diagram I, are converted to alcohols of formula III.1 by treatment with a demethylating agent such as boron tribromide. Conversion of alcohols of formula III.1 to bromides of formula V with a brominating agent, preferably carbon tetrabromide/triphenylphosphine, and subsequent treatment with a salt of thiophenol, such as sodium thiophenoxide, affords thioethers of formula III.2. Oxidation of thioethers of formula III.2 with an oxidizing agent, perferably m-chloroperbenzoic acid (m-CPBA) yields sulfoxides of formula III.3, which on heating in a solvent with a boiling point of at least 100xc2x0 C. (normal conditions), such as halogenated hydrocarbons, preferably ortho-dichlorobenzene, affords vinyl compounds of formula Ia. These transformations are depicted in Flow Diagram II. 
Allyl compounds of formula Ic are synthesized by the method depicted in Flow Diagram III. Alcohols of formula III.1 are treated with an oxidizing agent, such as pyridinium chlorochromate, and the resulting aldehydes of formula III.4 are treated with a silylating agent, such as trimethylsilylmethyl magnesium chloride, to afford compounds of formula III.5. Treatment of compounds of formula III.5 with an acid, such as acetic acid, affords allyl compounds of formula Ic. 
In a preferred embodiment of the present invention, the fluorine atoms attached to the carbon atoms of the double bond in the formula I compounds are in the (E)-configuration with respect to each other.
Compounds of formula I wherein the fluorine atoms at the double bond are in the (Z)-configuration may be prepared by isomerizing A certain intermediate compounds described hereinabove which are predominantly in the (E)-configuration using conventional procedures such as exposure to light.
The present invention provides intermediates of formula II, 
wherein Ar and R are as defined as above for compounds of formula I, and R2 is hydrogen or fluorine, for the preparation of compounds of formula I as depicted in flow diagram I, and
the optical isomers thereof, and the (E)- and (Z)-isomers thereof.
Preferred are compounds of formula II wherein Ar and R are as preferred for compounds of formula I described above.
Particularly preferred are compounds of formula II.A 
wherein Ar is as defined for formula I and R2 is hydrogen or fluorine, which are especially useful for the preparation of compounds of formula I wherein R is 2-methoxyethyl, vinyl, or allyl.
In a preferred embodiment of the present invention, the fluorine atoms attached to the carbon atoms of the double bond in compounds of formula II and II.A are in the (E)-configuration with respect to each other.
The present invention also provides intermediates of formula III, 
wherein Ar and Ar1 are defined as above for compounds of formula I and R3 is phenylthio-C2-C6-alkyl, phenylsulfinyl-C2-C6-alkyl, hydroxy-C2-C6-alkyl, formyl-C2-C5-alkyl, or C2-C6-alkyl vicinally substituted with hydroxy and trimethylsilyl, and
the optical isomers thereof, and the (E)- and (Z)-isomers thereof.
Intermediates of formula III are used in the preparation of compounds of formula I as depicted in flow diagrams II and III.
Preferred are compounds of formula III wherein Ar and Ar1 are as preferred for compounds of formula I described above.
In a preferred embodiment of the present invention, the fluorine atoms attached to the carbon atoms of the double bond in the formula III compounds are in the (E)-configuration with respect to each other.
Compounds of formula I are effective for controlling insect and acarid pests. Those compounds are also effective for protecting growing or harvested crops from damage caused by insect and acarid attack and infestation.
Insects controlled by compounds of formula I include Lepidoptera such as tobacco budworms, cabbage loopers, cotton boll worms, beet armyworms, southern armyworms and diamondback moths; Homoptera such as aphids, leaf hoppers, plant hoppers and white flies; Thysanoptera such as thrips; coleoptera such as boll weevils, colorado potato beetles, southern corn rootworms, western corn rootworms and mustard beetles; and Orthoptera such as locusts, crickets, grasshoppers and cockroaches. Acarina controlled by the compounds of this invention include mites such as two-spotted spider mites, carmine spider mites, banks grass mites, strawberry mites, citrus rust mites and leprosis mites.
Compounds of formula I are especially useful for the control of tobacco budworms, southern armyworms and corn rootworms.
In practice generally 10 ppm to 10000 ppm and preferably 100 ppm to 5000 ppm of a formula I compound, dispersed in water or another liquid carrier, is effective when applied to plants or the soil in which the plants are growing to protect the plants from insect and acarid attack and infestation.
Compounds of formula I are also effective for controlling insect and acarid pests when applied to the foliage of plants and/or to the soil or water in which said plants are growing in sufficient amount to provide a rate of 0.1 kg/ha to 4.0 kg/ha of active ingredient.
While compounds of formula I are effective for controlling insect and acarid pests when employed alone, they may also be used in combination with other biological chemicals, including other insecticides and acaricides. For example, the compounds of formula I may be used effectively in conjunction or combination with pyrethroids, phosphates, carbamates, cyclodienes, endotoxin of Bacillus thuringiensis (Bt), formamidines, phenol tin compounds, chlorinated hydrocarbons, benzoylphenyl ureas, pyrroles and the like.
Compounds of formula I may be formulated as emulsifiable concentrates, flowable concentrates or wettable powders which are diluted with water or other suitable polar solvent, generally in situ, and then applied as a dilute spray. Said compounds may also be formulated in dry compacted granules, granular formulations, dusts, dust concentrates, suspension concentrates, microemulsions and the like all of which lend themselves to seed, soil, water and/or foliage applications to provide the requisite plant protection. Such formulations or compositions of the present invention include a compound of formula I (or combinations thereof) admixed with one or more agronomically acceptable inert, solid or liquid carriers. Those compositions contain a pesticidally effective amount of said compound or compounds, which amount may vary depending upon the particular compound, target pest, and method of use. Those skilled in the art can readily determine what is a pesticidally effective amount without undue experimentation.